JSON Validator
Check that JSON is valid and find mistakes.
How to use the JSON Validator
- Paste your JSON
Or open a .json file.
- See the result
Valid, or the exact line and column of the problem.
- Fix and check again
It checks as you type.
Questions
Is it really free, with no sign-up?
Yes, completely. There's no sign-up, no login and no daily limit: just open the page and start. It works in your browser on any computer, phone or tablet with nothing to install, and your files are never uploaded — everything happens on your device.
What are the most common JSON mistakes?
A comma after the last item, single quotes instead of double quotes, and keys without quotes.
Is my data sent anywhere?
No. Everything runs in your browser, on your device — nothing you paste or open is uploaded.